Gas discharge device



Jan. 30, 1962 D. C. SUPPLY G. G. COLLINS, JR., ETAL GAS DISCHARGE DEVICE Filed Aug. 26, 1958 INVENTORS. GARRY 6'. COLL N5; Je

KEJTH 14 2 OLSON ATT ORQVE Y United States Patent 3,019,365 GAS DISCHARGE DEVICE Garry G. Collins, .lr., Long Branch, and Keith W. Olson, Neptune, N.J., assignors to The Bendix Corporation, a corporation of Delaware Filed Aug. 26, 1958, Ser. No. 757,285 Claims. (Cl. 313-213) The present invention relates to electron discharge devices and more particularly to cold cathode discharge devices.

Some applications require a cold cathode gas discharge device that has a very stable breakdown over a wide temperature range and a long operating life. One specific requirement was that the maximum variation in the breakdown and operating voltage be within i3% over a temperature range of -55 C. to +135 C. and with an operating life at +l35 C. of 10,000 pulses. Various known cold cathode tube geometries were tried but devices constructed in accordance thereto failed to meet the requirements.

The present invention provides a novel cold cathode discharge device in which the geometry provides a strong field between the anode and cathode, thus, providing stable breakdown and operating voltages during temperature cycling.

It is an object of the present invention to provide an improved electron discharge device.

Another object of the invention is to provide a novel cold cathode discharge device having extremely stable breakdown and operating voltage.

Another object of the invention is to provide a cold cathode discharge device having novel anode geometry.

Another object of the invention is to provide a novel cold cathode discharge device having a long operating life.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing, wherein two embodiments are illustrated by way of example.

In the drawing:

FIGURE 1 is a cutaway view of an electron discharge device illustrating one embodiment of the invention.

FIGURE 2 is a cross section view of the device of FIGURE 1 taken along the line 2-2.

FIGURE 3 is a cutaway view of an electron discharge device illustrating another embodiment of the invention.

FIGURE 4 is a cross section view of the device of FIGURE 3 taken along the line 44.

FIGURE 5 is a schematic diagram of a typical operating circuit.

In the drawing, the same reference numerals have been assigned to like parts in the various figures for simplicity.

Referring now to FIGURES l and 2, a cold cathode discharge device is indicated generally by the numeral 6 and has an envelope 7 of glass or other suitable material. The envelope 7 has a stem portion 8 through which connection pins 9 pass and are sealed therewith in a conventional manner. Mounted on a pair of the pins 9 is a cylindrical cathode 10 having an oxide coating 11 on the inner surface thereof. The cathode 10 may be of nickel with a barium strontium calcium oxide coating. It is understood, however, that other suitable material may be used. Mounted at either end of the cathode 10 are mica discs 12 and 13. A spot of radioactive material 14, such as cesium 137, may be provided on the mica 12 facing towards the inside of the cathode 10. It is understood that other radioactive material may be used.

A novel feature of the invention is the geometry of 3,019,365 Patented Jan. 30, 1962 anode 15 which comprises 4 rods 15a, 15b, 15c and 15d, spaced equidistant from the cathode 10. The rods 15a, 15b, 15c and 15d may be of nickel or any other suitable material. A band 16 of a conducting material connects the rods 15a, 15b, 15c and 15d and serves as a support therefor. The band 16, together with the anode assembly 15, is supported on one of the pins- 9. The rod 15a has an extension beyond the mica 13 upon which a getter 17 may be mounted. A splash mica 18 may be inserted between the getter 17 and the mica 13. The envelope 7 is filled with an inert gas or mixture of gases.

Refer now to FIGURES 3 and 4 in which the device 20 is similar in construction to that of FIGURE 1 except for the anode, hence, for a detailed description of the similar parts reference is made to the above description given for FIGURE 1. The device 20 has an anode 21 formed with four projections or vanes 21a, 21b, 21c and 21d of a suitable material, for example nickel. The vanes 21a, 21b, 21c and 21d form an angle of substantially degrees with each other and are positioned so that they are equidistant from the cathode 10. A tab 22 is provided on the anode 21 for connecting to one of the pins 9. A getter assembly 23 may 'be mounted on the anode 21.

In operation, the four vanes or projections 21a, 21b, 21c and 21:! provide a strong field between the anode and cathode, the field is concentrated on the four projections. The initial breakdown may occur between the cathode and any one of the four projections. When used in a circuit, such as that illustrated in FIGURE 5, with the proper voltage applied across the device, it breaks down and conducts. Preferably, the load resistance is of a value so that the device operates in a glow discharge. The operation of the device of FIGURE 1 is similar in that the four rods perform the same as the four projections.

In devices constructed in accordance with the above, the spread in breakdown voltage of an individual unit, over a temperature range of 55 C. to C., was less than four volts and was an average of two volts. The maximum spread in operating voltage, at a current of 25 ma. D.C., over the above temperature range was less than eight volts and an average of three volts.

Although only two embodiments of the invention have been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention.

What is claimed is:

l. A cold cathode gas discharge device comprising an envelope, a cylindrical cathode having an oxide coating on the inside thereof, an anode having four sections spaced equidistant from said cathode to form a concentrated field between said anode and said cathode, and an inert gas filling said envelope, said devices having a stable breakdown over a wide temperature range.

2. A cold cathode gas discharge device comprising a cylindrical cathode having an oxide coating on the inside thereof, an anode having four rods extending through said cathode and spaced equidistant therefrom, said rods forming a concentrated field between said anode and said cathode and a gas filled envelope enclosing said cathode and anode.

3. A cold cathode gas discharge device comprising a cylindrical cathode having an oxide coating on the inside thereof, an anode having four projections extending through and spaced equidistant from said cathode, said projections forming an angle of 90 degrees relative to each other and providing a concentrated field between said anode and said cathode, and a gas filled envelope enclosing said anode and cathode.

4. YA gas discharge device comprising a cylindrical cathode having a coating of cathode emissive material on the inner surface thereof, an anode positioned inside of said cathode and having a plurality of vanes extending to-' wards and spaced equidistant from said cathode, said vanes causing a concentrated field between said anode and said cathode and a gas filled envelope enclosing said anode and cathode.

,5. A gas discharge device comprising a cylindrical cathode having a coating of cathode emissive material on the inner surface thereof, a plurality of anodes extending through said cathode and spaced equidistant therefrom,

means connecting said anodes together, said plurality of anodes forming a concentrated field with said cathode and a gas filled envelope enclosing said anodes and said cathode.

References Cited in the file of this patent UNITED STATES PATENTS 1,897,473 Friedrichsen Feb. 14, 1933 1,902,936 Anderson Mar. 28, 1933 1,903,493 Beck Apr. 11, 1933 2,020,727 Gaidies Nov. 12, 1935 

